(A) Body weight (mean ± SEM, n = 4 pigs) of 4-month old pigs. (B) Percent longissimus dorsi, semitendinosus, semimembranosus, and triceps of body weight for 4-month old pigs. Data are reported as mean ± SEM (n = 4). *P < 0.05, **P < 0.01, ***P < 0.001. (C) Body weight (mean ± SEM, n = 4 pigs) of 16-month old pigs. *P < 0.05, **P < 0.01, ***P < 0.001. (D) Percent skeletal muscle of body weight for 16-month old pigs. Data are reported as mean ± SEM (n = 4). *P < 0.05, **P < 0.01, ***P < 0.001. (E) Percent longissimus dorsi, semitendinosus, semimembranosus, and triceps of body weight of 4-month old pigs. Data are reported as mean ± SEM (n = 4). *P < 0.05, **P < 0.01, ***P < 0.001. (F) The cross section of longissimus dorsi and subcutaneous fat between 6th and 7th ribs in 16-month old pigs. (G) The lion eye area (mean ± SEM, n = 4 pigs) of longissimus dorsi between the 6th and 7th ribs. *P < 0.05, **P < 0.01, ***P < 0.001. Black bar: Mstn+/+ (wild-type) pigs; white bar: Mstn−/− pigs.